The study of cell biology has been inseparable from the evolution of the microscope. The beginning of the cell biology can be visualized in the 15th century when da Vinci in 1485 has stressed upon the use of lenses in viewing small objects. The first compound microscope was made by Robert Hooke (1665). He examined thin slices of cork under his microscope and observed that the cork was composed of box-like compartments which were termed as the cells by him. Robert Brown was a palaeobotanist. He gave details of the cell nucleus and cytoplasmic streaming.